Zero delta temperature thermal link

ABSTRACT

An apparatus for transferring cryogenic refrigeration includes a cryocooler interface, a housing, a working fluid, a heat exchanger, a flexible thermal link, and a remote cartridge cold head. The cryocooler interface is thermally connected to a cryocooler providing a source of refrigeration. The refrigeration is passed from the crycooler into the heat exchanger via the cryocooler interface. The remote cartridge cold head is attached to a remote location. Heat is drawn from the remote location through the remote cartridge cold head and into the heat exchanger via the working fluid within the flexible thermal link and housing. Within the heat exchanger, heat is transferred from the working fluid to the refrigeration source, such as a cryocooler; accordingly, the remote location is cooled.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of international patent applicationNo. PCT/US2010/038328, entitled “ZERO DELTA TEMPERATURE THERMAL LINK,”filed on Jun. 11, 2010, which claims priority to U.S. provisional patentapplication No. 61/186,247, with the same title, filed on Jun. 11, 2009,the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to cryogenic refrigeration. More specifically, itrelates to the transfer of heat from a fixed location, such as acryocooler, to a remote location, such as a superconducting magnet.

2. Description of the Prior Art

Applying refrigeration to remote locations in a cryostat typicallyinvolves constructing conduction paths from fixed copper links and usingliquid cryogens provided by an open or closed loop. The fixed copperlinks create thermal and mechanical loads. Furthermore, the fixed copperlinks generate vibrations and are relatively complicated to install anduse.

What is needed in the art is an apparatus to eliminate the thermal andmechanical loads created by the fixed copper links.

What is also needed is an apparatus to reduce the transfer of vibrationsfrom the fixed copper links.

Yet another need in the art exists for an apparatus that facilitates usewhen compared with the maintenance of liquid cryogens in an open system.

Still another need in the art exists for an apparatus that facilitatesinstallation in view of the installation of a complicate closed-loopcryogenic system.

However, in view of the prior art considered as a whole at the time thepresent invention was made, it was not obvious to those of ordinaryskill in the art how the limitations of the art could be overcome.

SUMMARY OF INVENTION

The long-standing but heretofore unfulfilled need for an improvedapparatus for transferring heat from a fixed location to a remotelocation is now met by a new, useful, and nonobvious invention.

The novel apparatus transfers cryogenic refrigeration from a fixedlocation to a remote location. The apparatus generally includes acryocooler interface, a housing having a self-contained volume ofworking fluid, a heat exchanger, a flexible thermal link, and a remotecartridge cold head. The cryocooler interface is disposed on the surfaceof the housing and in thermal communication with the heat exchanger. Theheat exchanger is disposed within the housing and in thermalcommunication with the self-contained volume of working fluid. Theflexible thermal link extends from, and is in thermal communicationwith, the housing. The remote cartridge cold head is in thermalcommunication with the flexible link and provides a heat transfersurface.

In operation, the cryocooler interface is thermally connected to acryocooler providing refrigeration. The refrigeration is passed from thecryocooler into the heat exchanger via the cryocooler interface. Theremote cartridge cold head is attached to a remote location. Heat isdrawn from the remote location through the remote cartridge cold headand into the heat exchanger via the working fluid within the flexiblethermal link and housing. Within the heat exchanger, heat is transferredfrom the working fluid to the cryocooler and is replaced byrefrigeration from the cryocooler; accordingly, the remote location iscooled.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference should be made tothe following detailed description, taken in connection with theaccompanying drawings, in which:

The FIGURE is an elevated, diagrammatic view of an embodiment of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is an apparatus for transferring cryogenicrefrigeration from a fixed location, such as a cryocooler, to a remotelocation, such as a superconducting magnet. As depicted in the FIGURE,the apparatus generally includes cryocooler interface 10, housing 30,working fluid 25, heat exchanger 20, flexible thermal link 50, andremote cartridge cold head 60. Cryocooler interface 10 is disposed onthe surface of housing 30 and in thermal communication with heatexchanger 20. Heat exchanger 20 is disposed within housing 30 and inthermal communication with the self-contained volume of working fluid25. Flexible thermal link 50 extends from, and is in thermalcommunication with, housing 30. Remote cartridge cold head 60 is inthermal communication with flexible link 50 and provides a heat transfersurface.

The novel apparatus provides transfer of fixed position cold headrefrigeration to remote locations from the cryocooler and other sourcesof refrigeration at various cryogenic temperatures. It also providesrefrigeration at remote locations for both high-temperature andlow-temperature superconducting magnets and devices as well as for othercryogenic components with zero or essentially zero temperature rise fromthe original source of refrigeration.

The apparatus uses a working fluid that is self-contained. Thiseliminates complicated liquid or gas handling operational requirements.No gas bottles or liquid cryogen handling is required to implement andoperate this device.

The apparatus minimizes vibration transfer from the source of therefrigeration to the cryogenic component. It also minimizes thermal andother types of mechanical loads on the source of refrigeration. Thisreduces risk of damage dramatically in the case of thin-walled tubes incryocoolers.

In the FIGURE, cryocooler 15 provides the fixed source of refrigeration.The apparatus, however, will work with other sources of refrigeration.Cryocooler interface 10 connects directly to cryocooler 15. Therefrigeration from cryocooler 15 passes through cyrocooler interface 10and into heat exchanger 20. Heat exchanger 20 facilitates the transferof heat from working fluid 25 to the refrigeration. The heat transfercauses working fluid 25 to condense into the liquid phase. Housing 30contains a self-contained volume of working fluid 25 so that an operatordoes not need to transfer cryogens. Charging nozzle 40 places therequired mass of working fluid 25 into housing 30. Flexible thermal link50 transfers working fluid 25 from housing 30 to a location remote ofcryocooler 15. Remote cartridge cold head 60 provides a heat transfersurface at the remote location.

In operation, cryocooler interface 10 is thermally connected tocryocooler 15. Cryocooler 15 provides refrigeration. The refrigerationis passed from crycooler 15 into heat exchanger 20 via cryocoolerinterface 10. Remote cartridge cold head 60 is attached to a remotelocation. Heat is drawn from the remote location through remotecartridge cold head 60 and into heat exchanger 20 via working fluid 25within flexible thermal link 50 and housing 30. Working fluid 25,containing heat from the remote location, travels up flexible thermallink 50 and housing 30 and into heat exchanger 20. Within heat exchanger20, heat is transferred from working fluid 25 to cryocooler 15.

In a preferred embodiment, charging nozzle 40 is used only once duringmanufacturing and places the required mass of working fluid 25 intohousing 30. Accordingly, working fluid 25 is a self-contained volume andan operator does not need to transfer or otherwise handle cryogens.

Working fluid 25 is preferably helium, hydrogen, methane, nitrogen,oxygen, neon or fluorine or a combination thereof.

Remote cartridge cold head 60 preferably includes at least one hole tofacilitate heat transfer. Moreover, to further facilitate heat transfer,remote cartridge cold head 60 is formed from a high thermal conductingmaterial. In the FIGURE, remote cartridge cold head 60 is depicted as along cylinder but may be of any predetermined geometric shape.

It will be seen that the advantages set forth above, and those madeapparent from the foregoing description, are efficiently attained andsince certain changes may be made in the above construction withoutdeparting from the scope of the invention, it is intended that allmatters contained in the foregoing description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

1. An apparatus for transferring cryogenic refrigeration, comprising: aninterface adapted to thermally connect to a source of refrigeration; ahousing having a self-contained volume of working fluid, said interfacebeing disposed on a surface of said housing; a heat exchanger in thermalcommunication with said interface and disposed within said housing, saidheat exchanger transferring heat between said self-contained volume ofworking fluid and said source of refrigeration; a flexible thermal linkin thermal communication with, and extending from, said housing; and aremote cartridge cold head in thermal communication with said flexiblethermal link for providing a heat transfer surface at a location remoteto said source of refrigeration.
 2. An apparatus for transferringcryogenic refrigeration as in claim 1, further comprising: a chargingnozzle in mechanical communication with said heat exchanger housing. 3.An apparatus for transferring cryogenic refrigeration as in claim 1,wherein said source of refrigeration is a cryocooler.
 4. An apparatusfor transferring cryogenic refrigeration as in claim 1, wherein saidflexible thermal link is a hollow tube.
 5. An apparatus for transferringcryogenic refrigeration as in claim 1, wherein said remote cartridgecold head includes at least one hole.
 6. An apparatus for transferringcryogenic refrigeration as in claim 1, wherein said remote cartridgecold head is an elongated cylinder or other predetermined geometry. 7.An apparatus for transferring cryogenic refrigeration as in claim 1,wherein said self-contained volume of working fluid is helium.
 8. Anapparatus for transferring cryogenic refrigeration as in claim 1,wherein said self-contained volume of working cryogenic fluid ishydrogen.
 9. An apparatus for transferring cryogenic refrigeration as inclaim 1, wherein said self-contained volume of working cryogenic fluidis methane.
 10. An apparatus for transferring cryogenic refrigeration asin claim 1, wherein said self-contained volume of working cryogenicfluid is nitrogen.
 11. An apparatus for transferring cryogenicrefrigeration as in claim 1, wherein said self-contained volume ofworking cryogenic fluid is oxygen.
 12. An apparatus for transferringcryogenic refrigeration as in claim 1, wherein said self-containedvolume of working cryogenic fluid is neon.
 13. An apparatus fortransferring cryogenic refrigeration as in claim 1, wherein saidself-contained volume of working cryogenic fluid is fluorine.
 14. Anapparatus for transferring cryogenic refrigeration as in claim 1,wherein said self-contained volume of working cryogenic fluid is acombination of helium, hydrogen, methane, nitrogen, oxygen, neon, orfluorine.